First things first. Some of the lifeboats loaded and lowered under the supervision of first officer Murdoch left with empty seats too, lifeboat number 7 left with 28 occupants, lifeboat number 5 left with only slightly more than 40 people (based on my own counting, lifeboat number 3 left with around 32 occupants, emergency lifeboat 1 left with 12 occupants, lifeboat number 9 left with around 35-40 people, it goes on a bit like that and the only lifeboat that was filled to it fullest was lifeboat number 15 with around 68 occupants. Keep in mind I am a big admirer of Murdoch his career at sea, his personality as well as his actions that fateful night, but both he and Lightoller had the same factors against them. From reluctant passengers to empty decks, those sorts of problems were faced by both.
And secondly, the word to open the gangway door seemed to have been spread around as fifth officer Lowe recalled it too on the 13th day of the British Board of Trade inquiry (22nd of May 1912):
Then there's the physical evidence as well that human interference can be seen at the wreck. When the wreck was discovered in 1985 the forward port side gangway door was open, which was located right below lifeboat number 6 which Lightoller was loading at the time. The evidence that human interference opened these doors is that the folding gate in front of the door, that required a key, is in the folded position. The other gangway doors, including the one beside it, still has their gates closed. And while I disagree that boatswain Nichols and his men never made it back, as Lightoller claimed (per the excellent article by Brad Payne), I don't believe it's fair to say that Lightoller lied about the order given. Samuel Halpern, Arun Vajpey and I discussed it all a bit before in a previous thread.
Based on the evidence there is he likely wanted to have the lifeboats away quick, row for the light, drop the passengers off and row back to pick up more.
Based on captain Smith his actions near lifeboats number 6 and 8 it appears that he indeed believed women and children only should have been allowed. According to Helen Candee he shouted:
To Hugh Woolner and Mauritz Håkan Björnström-Steffansson (1883-1962)
But there we have a small problem. We don't know if captain Smith gave Murdoch any orders on how to fill the lifeboats. How is it possible to make an interpretation of a conversation that has no evidence that it ever took place? It's pure speculation, and while I have no doubt words were exchanged between Smith and Murdoch (who was captain's Smith his first officer for nearly 5 years on the RMS Adriatic (II) and RMS
Olympic) it's a bit unfair to judge Lightoller on it for we don't know what exactly was said.